Pyridoxine (vitamin B.sub.6) is a well known vitamin normally used as an adjunct is prophylaxis and treatment of multiple vitamin B complex deficiencies. It is also used in dermatoses, neuromuscular and neurological diseases.
An important synthetic procedure for pyridoxine involves the use of 4-methyl-5-cyanooxazole as a key intermediate. A typical synthetic procedure is that of Kimel et al., disclosed in U.S. Pat. No. 3,250,778, wherein 4-methyl-5-cyanooxazole is condensed with a 4,7-dihydro-1,3-dioxepin followed by acid hydrolysis of the resultant product to form pyridoxine. However, there is a continuing search to find more efficient and economical methods of producing the 4-methyl-5-cyanooxazole intermediate. Prior methods of preparing this intermedate have involved either heating 4-methyloxazole-5-carboxamides with phosphorus pentoxide or utilizing conventional amide dehydrating agents, such as phosphorus oxyhalides, to form the corresponding amides.
It has now been found that oxazole intermediates, preferably 4-methyl-5-cyanooxazole, useful in pyridoxine (vitamin B.sub.6) manufacture, may be prepared from diketene. Diketene is an inexpensive raw material and is presently used as such in vitamin A manufacture.